Comparison of Fracture Assessment of Offshore Pipelines with Flaws at Girth Welds

Offshore pipelines are one of the most effective methods for long-distance transportation of oil and gas. Currently, there are number of fitness for purpose procedures for assessing the acceptability of flaws in pipeline girth welds. One of these methods is fracture mechanics based procedures that is designed to: (1) relax workmanship flaw acceptance criteria and (2) prepare a route of determining acceptability of flaws found by Automatic Ultrasonic Test (AUT) instead of Radiographic Test (RT). The potential benefit of this procedure is a reduction in costs by minimizing the need for repair and the imposed delay. In this paper, workmanship and fracture mechanics based methods of defect assessment are discussed thoroughly and afterward are compared in order to determine each one range of applicability.